1. Field of the Invention
The present invention relates to a battery power source device for supplying high drive power required for large hybrid vehicles, a method for controlling the power source device, and a method for assigning an address.
2. Description of Related Art
A battery power source device employed as a power source for hybrid vehicles includes a battery pack block having a plurality of battery modules (e.g., 30 battery modules) connected in series, each battery module having a plurality of rechargeable batteries (e.g., 6 batteries) connected in series. To provide control to the operating conditions of the battery pack block, the battery power source device further includes a battery ECU (Electronic Control Unit) for sensing the voltage, current, and temperature of the battery pack block to detect abnormal states thereof or provide various types of control thereto based on the sensed results. Such a battery power source device is designed to supply power to the motor for driving the vehicle and to be charged by the power supplied from the generator thereof.
To supply higher power to larger vehicles, a plurality of battery pack systems each having the combination of the battery pack block and the battery ECU are designed to connect with each other serially and/or in parallel.
FIG. 2 shows the configuration of a battery power source device 30 having six battery pack blocks 1a to 1f connected serially in parallel. To control the operating condition of each of the battery pack blocks 1a to 1f, the battery pack blocks 1a to 1f are connected with battery ECUs 2a to 2f to form battery pack systems A to F, respectively, that are connected to a positive charge/discharge terminal 11 and a negative charge/discharge terminal 12.
The battery pack systems A to F are provided with respective current sensors 3a to 3f for detecting charge and discharge current, and various sensors (not shown) for detecting the voltage and temperature of each battery module, and the ambient temperature of the battery pack blocks 1a to 1f, respectively. The output from each sensor is delivered to their respective battery ECUs 2a to 2f. The battery ECUs 2a to 2f monitor the operating condition of the respective battery pack blocks 1a to 1f to check for any abnormal state based on the delivered voltage, current, and temperature as well as to provide control to a cooling device, such as an air blower, provided in each of the battery pack blocks 1a to 1f based on the detected temperatures. The battery ECUs 2a to 2f also calculate SOC (State of Charge or the quantity of electric charge accumulated relative to the battery capacity) from the delivered voltage, current, and temperature. The SOC and detected values such as voltage are delivered to external devices as the data on the operating condition of the battery pack blocks 1a to 1f, and for the hybrid vehicle, to a vehicle control ECU for controlling charge and discharge operations on the battery power source device 30.
With the battery power source device 30 including a plurality of battery pack systems A to F, there is a problem that any failure of one battery pack block have detrimental effects on the entire battery power source device, resulting in a decreased power supply to the vehicle. For example, suppose that a short circuit has occurred in a rechargeable battery that constitutes the battery pack block 1c of the battery pack system C. This causes a drop in the output voltage of the battery pack block 1c, which is lower than the voltage of the other battery pack blocks 1a and 1e connected in parallel thereto. Thus, a current from the other battery pack blocks 1a, 1b, 1e, and 1f flows into the battery pack block 1c, creating imbalances in capacity between the battery pack blocks and, thereby dropping the supply power delivered from the positive charge/discharge terminal 11 and the negative charge/discharge terminal 12.
On the other hand, to control the operating condition of each of the battery pack systems A to F from the vehicle side and transmit information between the battery pack systems A to F, it is necessary to identify each of the battery pack systems A to F by providing an address thereto. In general, an address number is stored in a memory to, set the address; however, this memory storing individual address numbers can result in an increase in cost and cause the battery pack systems A to F to be incompatible with other equivalent systems. There is also a possibility of installing a different type of system upon assembly or replacement.